[t]he Lorentz force \( \left[ e\textbf {E}+\frac{e}{c}\textbf {v} \times \textbf {B} \right] \)  does not appear anywhere in the fundamental theory, but appears only as an approximation holding in the classical limit. It would therefore seem natural at this point to propose that, in quantum mechanics, the fundamental physical entities are the potentials, while the fields are derived from them by differentiations [1]}.
